The photoprocessing of photograph film including prints typically involve sequential contacting with various chemicals such as developers, fixers and the like. These photographic materials are well-known in the art, and require no detailed discussion or description here. The contacting is commonly carried out in a processing drum which has to be continuously turned or rotated about its longitudinal axis in order that the chemicals be uniformly distributed and contacted with the film. Various motor drives have been proposed for the rotation of the processing drum. Known motor drives have a tendency to walk the tube off one end or other unless carefully leveled and then of course will still have the same problem eventually. The present invention, by virtue of a three wheel operation, always guarantees that the tube finds a center balance. It will even climb up hill to center in the event of an unlevel base. The three wheel system allows an unbalanced drum to tip. The tip also causes the drum to become unparallel with the wheel axis on a horizontal plane. This lack of parallelism causes the drum to be driven toward center until it becomes balanced. The major feature of this invention is the self-centering capability.
Thus, the present invention solves a significant problem in this art, and it is to be expected that the present invention will be widely adopted by those skilled in the art.